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In its review of the possible side effects of the AstraZeneca COVID-19 vaccine, the European Medicines Agency (EMA) again concluded that the vaccine is safe and effective and that the benefits of protecting against COVID-19 outweigh any possible risk.
But the EMA says it cannot rule out a link between rare cases of thrombosis with thrombocytopenia with the vaccine.
The EMA's announcement highlighting the safety of the AstraZeneca vaccine came at a press conference which, puzzlingly, took place at exactly the same time as a UK press conference in which it was recommended not to use the AstraZeneca vaccine in children under 30 years of age if an alternative vaccine was available.
Speaking at the EMA press conference on April 7, Emer Cooke, EMA Executive Director, said: "Our review found that the AstraZeneca vaccine is not associated with an increased risk of global thromboembolic events or blood clots, but there have been a small number of very rare but very serious bleeding disorders which triggered a more focused examination. "
"Based on the available evidence and based on several days of analysis, we still cannot definitively rule out a link between these serious bleeding disorders and the vaccine."
The committee has therefore raised awareness of this as a possible risk and will include it in the product information, drawing attention to these possible rare diseases and educating healthcare professionals and those vaccinated to help detect and mitigate side effects. possible.
The EMA advises patients to seek immediate medical attention if they experience the following symptoms: shortness of breath; chest pain; swelling of the legs; persistent abdominal pain; neurological symptoms, including severe and persistent headache or blurred vision; or tiny spots of blood under the skin beyond the injection site.
The agency is also launching additional investigations to better understand these rare cases and conduct targeted studies.
UK issues different advice
Addressing the decision of various European countries (and now the UK) not to use AstraZeneca in certain younger populations, Cooke said the EMA cannot advise individual countries on how they should use the AstraZeneca. various vaccines available.
"It is very important to stress that when a country makes a decision about vaccination, it does so with full knowledge of that particular population, of what is available and of the particular risk factors of that population," he said. she commented.
"The EMA's job is to look at the vaccine and see if it's safe and effective and if the benefit outweighs the risk," she said. "It is important that national authorities have the right scientific evidence to make their decisions, but they make decisions in the context of their populations and their immunization campaigns. Our job is to provide the right vaccine information so that they can make those informed decisions, "she noted.
Sabine Straus, MD, chair of the EMA Pharmacovigilance Risk Assessment Committee (PRAC), added: "We have been working around the clock on this review. Our conclusion is that the benefit of the AstraZeneca vaccine far outweighs the risks. no evidence of a quality problem with a particular lot of vaccine. "
Straus noted that the number of overall thromboembolic events after administration of the AstraZeneca vaccine is lower than expected in the total population. "Since the vaccine is effective in reducing COVID-19, which itself carries an increased risk of blood clots, it is likely that the vaccination will result in an overall reduction in blood clots."
However, she said they had seen "a few very rare case reports" describing unusual events specific to a combination of thrombosis and thrombocytopenia and bleeding.
"In a few cases, tiny clots develop in several blood vessels in the first 7 to 14 days after vaccination - a condition called disseminated intravascular coagulation (DIC). Additionally, in a few cases, clots have developed in the blood vessels draining blood from the brain, a condition known as cerebral venous sinus thrombosis (CVST). These conditions are linked to low levels of blood platelets also known as thrombocytopenia. "
But Straus concluded: "The evidence we have is not sufficient to conclude with certainty whether these adverse events are caused by the vaccine or not."
She said the PRAC will continue to collect more information on these conditions, including further studies.
Confusion over numbers
There appears to be some confusion over the actual number of these events that have been reported, with individual countries reporting higher numbers than the EMA.
During the EMA press conference, Straus stressed that these events are very rare. "Last night (April 6), 7 cases of DIC and 18 cases of CVST were reported out of 20 million people who received the AstraZeneca vaccine," she reported.
She added that among the CVST cases, 7 were from Germany, 3 from Italy, 2 from Norway, 1 from Spain, 3 from the UK and 2 from India.
While at the UK press conference it was disclosed that there had been 79 UK reports of blood clotting cases accompanied by low platelet counts following the use of the AstraZeneca vaccine, of which 44 classified as CVST with thrombocytopenia .
Different recommendations for age groups
There also appears to be some difference of opinion on the benefit / risk ratio in the younger age group.
Speaking at the EMA press conference, Straus said: "Our review showed that there is a predominance of these rare thrombotic events combined with thrombocytopenia in certain groups - especially in women and younger women. But it is still quite premature to conclude on one group because the background risk of thrombosis may be different in different groups and it is also possible that more people have received this vaccine in certain groups in different countries. The potential for different risk levels is part of our subsequent assessments. "
In the UK, Anthony Harnden, Vice Chairman of the UK Joint Committee on Vaccination and Immunization (JCVI), said: "We have decided that the benefit / risk ratio of AstraZeneca vaccine in people under 30 years of age does not increase. not really stack. "
Harnden said the age cutoff was based on a risk-benefit assessment. "It is clear that the benefits of the vaccine increase with age. A 50-year-old will benefit much more than a much younger person, and people between the ages of 30 and 39 will benefit more than those between the ages of 20 and 20. 29 years old. But there seems to be a slight gradient in risk towards young people, "he said." We felt that the benefits outweighed the risk in people over 30 years old. But in those under 30, the benefits and risks seem more similar. "
Harnden says the UK opinion does not disagree with the EMA. "The EMA and the UK regulatory authority have cleared the vaccine for all age groups. They believe it is safe for all adults. They have left it up to individual countries to make their own decisions on the way it is used, "he added. "We're not saying the vaccine isn't safe. We're just saying the benefit / risk ratio is such that we might be more careful in the younger age group."
He stressed that it is always important for those under 30 to get vaccinated. "The risk of severe COVID is very low in this age group, but the risks of long COVID are not low. About 30% of people with COVID-19 have long-term symptoms. There are other vaccines available. available in the UK, "he noted. . "Some people under 30 may have to wait a week or two longer than before, but there will be alternatives."
Harnden indicated that if someone has received a first dose of the AstraZeneca vaccine, they should continue and receive the second dose. "We have not yet seen a single case of thrombosis with thrombocytopenia after the second dose, but we have not yet administered so many second doses. We do not recommend mixing the vaccines at this time," he said. he adds.
At the EMA press conference, Cooke stressed the importance of getting vaccinated.
"I think we have to continually remind ourselves of what a difficult position we find ourselves in," she said. "This pandemic is causing thousands of deaths every day. We have safe and effective vaccines to prevent deaths and hospitalizations. We need to use these vaccines."
She added: "If it was me, I would be vaccinated tomorrow, but if anything happened to me after the vaccination, I would like to know what to do. And that is what we are saying today."
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